Electrochemistry of a Glucose Sensor

Cyclic Voltammetry of ferrocene carboxylic acid (FCA) in aqueous solution, in the presence of glucose and glucose oxidase (GOx). The 'blank' (blue) signal shows the result when glucose is absent.

Glucose is oxidized by electrochemically generated Fe(III) in FCA+. The FCA+ is continuously regenerated by the electrode under oxidizing conditions. The size of the anodic current depends on the enzyme and glucose concentrations.